• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1322-1327
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• 2010

Ready-mixed shotcrete mixed with high quality materials and can be controled shotcrete quality is producted in plants and transported to construction fields, so do not need a field batch plant. In this study, the field construction system that can be applied Ready-mixed Shotcrete to construction fields was proposed, and the all-in-one silo that was the key component of the field construction system was design. It was performed to evaluate the constructability that the field construction process analysis in case of applying a field batch plant and the all-in-one silo, the cost analysis of the material production and transport in a road tunnel was also performed to evaluate the economic feasibility of Ready-mixed shotcret.

• Transactions of Materials Processing
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• v.8 no.2
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• pp.127-134
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• 1999

This study suggests the practical method which can reduce the lead time of the field trial and design of the dies. The virtual manufacturing, with which the die design is evaluated by computer analysis, reveals the impropriety of a design before die makings. Three methods for reducing the die making process occupying over 60% of the automotive development are like follows: First, the crack and wrinkle occurrence can be prevented by virtually adjusting the blank holding force and drawbead force with a computer simulation. Second, the parts which can not remove the forming defects in spite of the adjustment of forming parameters need to modify the part geometry or punch temporary shape. Third, the simulation before field trial, and field trial simulation can be effectively used in die design.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.3
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• pp.243-254
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• 1996

The main purpose of this study is to investigate the collection efficiency characteristics of a cylindrical ESP. To do that, it is necessary to analyze the electric field, gas flow field, and mechanism of particle movement by numerical simulation based on EHD model. For a gas flow field, Navier-Stokes equation involving the electric source term was solved by SIMPLE algorithm. In case of the electric field, the current continuity and electric field equations were solved by S.O.R. method. The analysis of particle movement was performed on the basis of PSI-CELL model from the Lagrangian viewpoint. The results showed that the influence on the gas flow field by the electric field is almost negligible in a cylindrical ESP. The particle drift velocity $V_P$ toward the collection surface is increased continuously by the electrostatic force due to the rise of particle charge as the particle is moving to the flow direction and the particle size becomes larger. The collection efficiency is to quitely higher with the increase of applied voltage for the same particle size, while becomes smaller as the inlet velocity is increased.

• Nuclear Engineering and Technology
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• v.30 no.3
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• pp.202-211
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• 1998

Interfacial stresses at two-material interfaces and initial displacement field over the entire domain are obtained by modifying the potential energy functional with a penalty function, which enforces continuity of the stresses at the interface of two materials. Based on the initial displacement field and interfacial stresses, a new methodology to generate a continuous stress field over the entire domain has been proposed by combining the modified projection method of stress-smoothing and Loubignac's iterative method of improving the displacement field. Stress analysis is carried out on two examples made of dissimilar materials : one is a two-material cantilever composed of highly dissimilar materials and the other is a zirconium-lined cladding tube made of slightly dissimilar materials. Results of the analysis show that the proposed method provides an improved continuous stress field over the entire domain, and accurately predicts the nodal stresses at the interface, while the conventional displacement-based finite element method produces significant stress discontinuities at the interface. In addition, the total strain energy evaluated from the improved continuous stress field converges to the exact value in a few iterations.

• Structural Engineering and Mechanics
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• v.62 no.4
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• pp.497-506
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• 2017

A low damage self-centering braced frame equipped with post-tensioning strands is capable of directing damage to replaceable butterfly-shaped fuses. This paper investigates the seismic performance of rocking braced frame under near-field pulse-like ground motions compared to far-field records. A non-linear time history analysis is performed for twelve self-centering archetypes. A sensitivity analysis is carried out to examine the influences of ground motion types and modeling parameters. Findings represent the proper efficiency of the self-centering system under both far-field and near-field pulse-like ground motions.

• Design & Manufacturing
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• v.15 no.1
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• pp.66-71
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• 2021

In this study, die turning injection(DTI) mold design for manufacturing reservoir fluid tanks used for cooling in-vehicle batteries, inverters, and motors was conducted based on multi-field CAE. Part design, performance evaluation, and mold design of the reservoir fluid tank was performed. The frequency response characteristics through modal and harmonic response analysis to satisfy the automotive performance test items for the designed part were examined. Analysis of re-melting characteristics and structural analysis of the driving part for designing the rotating die of the DTI mold were performed. Part design was possible when the natural frequency performance value of 32Hz or higher was satisfied through finite element analysis, and the temperature distribution and deformation characteristics of the part after injection molding were found through the first injection molding analysis. In addition, it can be seen that the temperature change of the primary part greatly influences the re-melting characteristics during the secondary injection. The minimum force for driving the turning die of the designed mold was calculated through structural analysis. Hydraulic system design was possible. Finally, a precise and efficient DTI mold design for the reservoir fluid tank was possible through presented multi-field CAE process.

• International Journal of Highway Engineering
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• v.17 no.1
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• pp.51-58
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• 2015

PURPOSES : The objective of this study is to compare the densities of asphalt pavements measured both in the field and in the laboratory, and also to evaluate the applicability of field density measuring equipment, such as the pavement quality indicator (PQI), by using statistical analysis. METHODS : For the statistical analysis of the density measured from asphalt pavement, student t-tests and a coefficient of correlation are investigated. In order to compare the measured densities, two test sections are prepared, with a base layer and an intermediate layer constructed. Each test section consists of 9 smaller sections. During construction, the field densities are measured for both layers (base and intermediate) in each section. Core samples are extracted from similar regions in each section, and moved to the laboratory for density measurements. All the measured densities from both the field and laboratory observations are analyzed using the selected statistical analysis methods. RESULTS AND CONCLUSION : Based on an analysis of measured densities, analysis using a correlation coefficient is found to be more accurate than analysis using a student t-test. The correlation coefficient (R) between the field density and the core density is found to be very low with a confidence interval less than 0.5. This may be the result of inappropriate calibration of the measuring equipment. Additionally, the correlation coefficient for the base layer is higher than for the intermediate layer. Finally, we observe that prior to using the density measuring equipment in the field, a calibration process should be performed to ensure the reliability of measured field densities.

• Journal of Information Processing Systems
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• v.18 no.3
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• pp.359-373
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• 2022

The new crown pneumonia (COVID-19) has become a global epidemic. The disease has spread to most countries and poses a challenge to the healthcare system. Contact tracing technology is an effective way for public health to deal with diseases. Many experts have studied traditional contact tracing and developed digital contact tracking. In order to better understand the field of contact tracking, it is necessary to analyze the development of contact tracking in the field of computer science by bibliometrics. The purpose of this research is to use literature statistics and topic analysis to characterize the research literature of contact tracking in the field of computer science, to gain an in-depth understanding of the literature development status of contact tracking and the trend of hot topics over the past decade. In order to achieve the aforementioned goals, we conducted a bibliometric study in this paper. The study uses data collected from the Scopus database. Which contains more than 10,000 articles, including more than 2,000 in the field of computer science. For popular trends, we use VOSviewer for visual analysis. The number of contact tracking documents published annually in the computer field is increasing. At present, there are 200 to 300 papers published in the field of computer science each year, and the number of uncited papers is relatively small. Through the visual analysis of the paper, we found that the hot topic of contact tracking has changed from the past "mathematical model," "biological model," and "algorithm" to the current "digital contact tracking," "privacy," and "mobile application" and other topics. Contact tracking is currently a hot research topic. By selecting the most cited papers, we can display high-quality literature in contact tracking and characterize the development trend of the entire field through topic analysis. This is useful for students and researchers new to field of contact tracking ai well as for presenting our results to other subjects. Especially when comprehensive research cannot be conducted due to time constraints or lack of precise research questions, our research analysis can provide value for it.

• Journal of Family Resource Management and Policy Review
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• v.13 no.3
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• pp.247-280
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• 2009

The purpose of this study was to investigate the actual conditions of management of the healthy family field practicum and to present suggestions for its improvement. For this purpose, a preliminary investigation, survey, data analysis, interview as secondary source, and final data analysis were processed as research methods. The subjects of this study were the 42 supervisors in the centers which oversee the field practicum experience and the 12 supervisors in the centers which do not oversee the field practicum experience. 3 supervisors were interviewed to inquire about the reformation of field instruction in Healthy Family Support Centers. Analysis was made of the general characteristics of the above-mentioned 54 supervisors, including sex, age, academic background, certificate of qualification, class of position, and length of career related to the healthy family program. The environment of the field practice, such as the numbers of students supervised, time of field practice, practice hours, and so on, was examined in the centers which oversee the field practicum experience. The actual condition of operation investigated was divided into the preparatory stage, the early stage, the midterm stage, and the end stage. Research was conducted on the improvement of the field practicum, including the proper number of students supervised, adequate practice hours, interaction with universities or colleges, obstacles to the field practicum, and of practicum. The possibility and preparation of a further field practicum was conducted for 12 Healthy Family Support Centers, by inquiring about (a) the reasons for not overseeing the field practicum experience and (b) the needs of universities or colleges for a field practicum. The 54 supervisors surveyed suggested a particular need for improvement in human resources, the space of field instruction, system of field practicum, length of practice hours, orientation for students etc. This study investigated the actual conditions and suggested improvements of the field practicum in Healthy Family Support Centers. Therefore, its results should be meaningfully used to develop the Field Practicum for the Healthy Family and to conduct further studies.

• Explosives and Blasting
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• v.29 no.2
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• pp.32-42
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• 2011

For blasting vibration analysis, there are mostly two methods, firstly, far field vibration analysis to estimate limit of building damage, secondly, near field subterranean vibration analysis to estimate rock damage and subterranean structure facilities. The former has been mainly used in our country and aboard, the latter is mostly analysed by using Homberg's model. In this model, basic input data are acquired in far field surface vibration. But in the consideration of the results of being conducted in this area over the past few decade, it is required that Homberg's model is modified. For the purpose of this, measurements of near field vibration were first conducted in our country. But it was only proposed the measurement method and the method of analysis or prediction was not suggested. Accordingly, in this paper, measurements of near field subterranean vibration were conducted and the method of analysis or prediction of near field subterranean vibration would be suggested.